MECHANICAL ENGINEERING CONCEPTUAL INTERVIEW QUESTIONS ASK IN PSU EXAMS

Contents show

MECHANICAL ENGINEERING CONCEPTUAL INTERVIEW QUESTIONS ASK IN PSU EXAM

What is mechanical engineering?

Answer: Mechanical engineering is a branch of engineering that deals with the design, construction, and maintenance of mechanical systems, including machines, tools, and mechanical components.

What are the types of loads in mechanical engineering?

Answer: The types of loads in mechanical engineering include static loads, dynamic loads, impact loads, and cyclic loads.

What is the difference between stress and strain?

Answer: Stress is the force applied per unit area, while strain is the resulting deformation of the material.

What are the different types of materials used in mechanical engineering?

Answer: The different types of materials used in mechanical engineering include metals, polymers, ceramics, and composites.

What is the difference between heat and temperature?

Answer: Heat is the total amount of energy in a substance, while temperature is a measure of the average kinetic energy of the particles in a substance.

What is the difference between a compressor and a pump?

Answer: A compressor is used to increase the pressure of a gas, while a pump is used to increase the pressure of a liquid.

What is the difference between a pulley and a gear?

Answer: A pulley is a simple machine used to change the direction of a force, while a gear is a mechanical component used to transmit torque and power.

What is the difference between a machine and a mechanism?

Answer: A machine is a combination of mechanisms designed to perform a specific task, while a mechanism is a system of parts that work together to produce a specific motion or force.

What is the difference between a bearing and a bushing?

Answer: A bearing is a machine element used to reduce friction and support a load, while a bushing is a cylindrical component used as a bearing surface.

What is the difference between a shaft and an axle?

Answer: A shaft is a rotating component used to transmit power, while an axle is a stationary component used to support and rotate wheels or other rotating components.

What is the difference between a closed loop and an open loop control system?

Answer: A closed loop control system uses feedback to adjust the system output to match a desired input, while an open loop control system does not use feedback and relies on a predetermined set of instructions.

What is the difference between a compressor and a turbine?

Answer: A compressor is used to increase the pressure of a gas, while a turbine is used to convert the energy from a fluid or gas into mechanical energy.

What is the difference between a solenoid and a relay?

Answer: A solenoid is an electromechanical device that converts electrical energy into linear motion, while a relay is an electrical switch that allows a low-power signal to control a high-power circuit.

What is the difference between a worm gear and a spur gear?

Answer: A worm gear is used for high reduction ratios and low speeds, while a spur gear is used for moderate to high speeds and low to moderate reduction ratios.

What is the difference between fatigue and creep?

Answer: Fatigue is the failure of a material due to repeated cyclic loading, while creep is the gradual deformation of a material over time due to a constant load.

What is the difference between a pneumatic system and a hydraulic system?

Answer: A pneumatic system uses compressed air to transmit power, while a hydraulic system uses a liquid, typically oil, to transmit power.

What is the difference between a centrifugal pump and a positive displacement pump?

Answer: A centrifugal pump uses centrifugal force to transfer fluid, while a positive displacement pump uses a mechanical mechanism to transfer fluid.

What is the difference between a cantilever beam and a simply supported beam?

Answer: A cantilever beam is supported at one end, while a simply supported beam is supported at both ends.

What is the difference between hardness and toughness?

Answer: Hardness is a materialโ€™s resistance to indentation or scratching, while toughness is a materialโ€™s ability to resist fracture or deformation under stress.

What is the difference between a cam and a follower?

Answer: A cam is a mechanical component used to convert rotary motion into linear motion, while a follower is a component that moves along the surface of a cam to produce a specific motion or force.

What is the difference between stress and strain rate?

Answer: Stress rate is the rate at which stress is applied to a material, while strain rate is the rate at which deformation occurs in response to the applied stress.

What is the difference between a power screw and a machine screw?

Answer: A power screw is used to transmit power or motion between rotating and linear motion, while a machine screw is used to fasten two objects together.

What is the difference between a synchronous motor and an induction motor?

Answer: A synchronous motor runs at a fixed speed and is used for precision applications, while an induction motor runs at varying speeds and is used for general applications.

What is the difference between a spring and a damper?

Answer: A spring is a component that stores potential energy, while a damper is a component that dissipates energy.

What is the difference between a strain gauge and a load cell?

Answer: A strain gauge is a device that measures the strain in a material, while a load cell is a device that measures the force or weight applied to it.

What is the difference between a heat engine and a refrigeration cycle?

Answer: A heat engine converts thermal energy into mechanical work, while a refrigeration cycle uses mechanical work to transfer heat from a low-temperature region to a high-temperature region.

What is the difference between a compressor and a fan?

Answer: A compressor increases the pressure of a gas, while a fan increases the flow of air.

What is the difference between ductile and brittle materials?

Answer: Ductile materials can undergo large deformation before fracturing, while brittle materials fracture with little or no deformation.

What is the difference between a differential and a gearbox?

Answer: A differential is used to distribute power between two wheels, while a gearbox is used to transmit power between a motor and a drivetrain.

What is the difference between a piston engine and a turbine engine?

Answer: A piston engine uses pistons to convert thermal energy into mechanical work, while a turbine engine uses turbines to convert fluid energy into mechanical work.

What is the difference between a closed cycle gas turbine and an open cycle gas turbine?

Answer: In a closed cycle gas turbine, the working fluid is continuously recycled, while in an open cycle gas turbine, the working fluid is discharged to the atmosphere after each cycle.

What is the difference between a pressure vessel and a storage tank?

Answer: A pressure vessel is designed to contain fluids at high pressure, while a storage tank is designed to store fluids at atmospheric pressure.

What is the difference between a sensor and a transducer?

Answer: A sensor detects a physical quantity and converts it into an electrical signal, while a transducer converts one form of energy into another.

What is the difference between a batch process and a continuous process?

Answer: A batch process produces a fixed quantity of a product in one batch, while a continuous process produces a product continuously without interruption.

What is the difference between a thermocouple and a RTD (resistance temperature detector)?

Answer: A thermocouple measures temperature by detecting the voltage produced by a temperature difference between two metals, while an RTD measures temperature by detecting changes in the electrical resistance of a material with temperature.

What is the difference between a flange and a gasket?

Answer: A flange is a component used to connect two sections of pipe or other equipment, while a gasket is a sealing element that is placed between two flanges to prevent leakage.

What is the difference between a static and a dynamic load?

Answer: A static load is a load that is applied to a structure or component and remains constant, while a dynamic load is a load that varies over time.

What is the difference between a slip ring and a commutator?

Answer: A slip ring is a rotating electrical connector used to transfer power or signals between stationary and rotating parts, while a commutator is a component used in certain types of motors to reverse the direction of current flow in the armature.

What is the difference between a thermoplastic and a thermosetting plastic?

Answer: A thermoplastic can be melted and reformed multiple times without undergoing chemical change, while a thermosetting plastic irreversibly hardens when heated.

What is the difference between a gas and a vapor?

Answer: A gas is a substance that is in a gaseous state at room temperature, while a vapor is the gaseous form of a substance that is normally a liquid or a solid at room temperature.

What is the difference between a single-phase and a three-phase power system?

Answer: A single-phase power system has only one voltage waveform, while a three-phase power system has three voltage waveforms that are 120 degrees apart.

What is the difference between an electric motor and an electric generator?

Answer: An electric motor converts electrical energy into mechanical energy, while an electric generator converts mechanical energy into electrical energy.

What is the difference between a linear and a nonlinear system?

Answer: A linear system has a proportional relationship between the input and output, while a nonlinear system has a non-proportional relationship between the input and output.

What is the difference between an impulse and a reaction turbine?

Answer: An impulse turbine operates by a high-velocity jet of fluid impinging on blades, while a reaction turbine operates by fluid flow through a set of fixed and moving blades.

What is the difference between an AC and a DC motor?

Answer: An AC motor operates on alternating current and is commonly used in household appliances and industrial applications, while a DC motor operates on direct current and is commonly used in electric vehicles and industrial applications.

What is the difference between a cantilever and a simply supported beam?

Answer: A cantilever beam is supported at only one end and carries a load at the other end, while a simply supported beam is supported at both ends and carries a load in the middle.

What is the difference between a solid, liquid, and gas?

Answer: A solid has a definite shape and volume, a liquid has a definite volume but no definite shape, and a gas has no definite shape or volume.

What is the difference between a centrifugal pump and a positive displacement pump?

Answer: A centrifugal pump uses centrifugal force to move fluid through a system, while a positive displacement pump moves fluid by trapping a fixed amount of fluid and forcing it through a system.

What is the difference between a beam and a column?

Answer: A beam is a horizontal or inclined structural member that supports a load, while a column is a vertical structural member that supports a load.

What is the difference between a bolt and a screw?

Answer: A bolt is a fastener that is used with a nut to join two or more objects, while a screw is a fastener that is used to join two or more objects directly by threading into one of the objects.

What is the difference between a frequency and a wavelength?

Answer: Frequency is the number of cycles of a wave that occur in one second, while wavelength is the distance between two consecutive points on a wave that are in phase.

What is the difference between a manometer and a pressure gauge?

Answer: A manometer measures fluid pressure by measuring the height of a fluid column, while a pressure gauge measures fluid pressure by converting it into an electrical signal.

What is the difference between a solid state and a vacuum tube device?

Answer: A solid-state device uses semiconductor materials to control the flow of electricity, while a vacuum tube device uses a vacuum to control the flow of electricity.

What is the difference between a stepper motor and a servo motor?

Answer: A stepper motor moves in fixed increments, while a servo motor rotates to a precise position based on feedback from a sensor.

What is the difference between a gearbox and a transmission?

Answer: A gearbox is a mechanical device that transmits power and torque from one component to another at a different speed or torque, while a transmission is a mechanical device that transmits power and torque from an engine to the wheels of a vehicle.

What is the difference between a strain gauge and a load cell?

Answer: A strain gauge measures the deformation or strain of a material due to a force or load, while a load cell measures the force or weight applied to it.

What is the difference between a root cause and a symptom?

Answer: A root cause is the underlying reason for a problem or issue, while a symptom is a manifestation of the problem or issue.

What is the difference between a hydraulic and a pneumatic system?

Answer: A hydraulic system uses a liquid to transmit power, while a pneumatic system uses a gas, typically compressed air, to transmit power.

What is the difference between a stepper motor and a brushless DC motor?

Answer: A stepper motor moves in fixed increments, while a brushless DC motor rotates continuously with feedback from a sensor.

What is the difference between a primary and a secondary cell?

Answer: A primary cell is a disposable battery that cannot be recharged, while a secondary cell is a rechargeable battery that can be charged and discharged multiple times.


What is the difference between a bearing and a bushing?

Answer: A bearing is a machine element that supports a rotating shaft, while a bushing is a machine element that supports a stationary shaft or sleeve.

What is the difference between a cam and a follower?

Answer: A cam is a rotating or sliding element that imparts a specified motion to a follower, while a follower is a machine element that follows the motion of a cam.

What is the difference between a fan and a blower?

Answer: A fan is a machine that moves air in a direction perpendicular to the fan blade axis, while a blower is a machine that moves air in a direction parallel to the blower axis.

What is the difference between a horizontal and a vertical milling machine?

Answer: A horizontal milling machine has the spindle mounted horizontally, while a vertical milling machine has the spindle mounted vertically.

What is the difference between a torque and a moment?

Answer: Torque is the rotational equivalent of force, while moment is the tendency of a force to rotate an object about an axis.

What is the difference between a flywheel and a pulley?

Answer: A flywheel is a rotating mechanical device that stores kinetic energy, while a pulley is a machine element that changes the direction or magnitude of a force.

What is the difference between a gear and a pulley?

Answer: A gear is a machine element that transmits rotational motion and power between two shafts, while a pulley is a machine element that changes the direction or magnitude of a force.

What is the difference between a centrifugal and a reciprocating compressor?

Answer: A centrifugal compressor compresses gas by increasing its velocity and then converting that velocity into pressure, while a reciprocating compressor compresses gas by reducing the volume of the compression chamber.

What is the difference between a beam and a truss?

Answer: A beam is a structural element that supports a load by resisting bending, while a truss is a structural element that supports a load by resisting tension and compression.

What is the difference between a gear pump and a vane pump?

Answer: A gear pump uses meshing gears to move fluid through a system, while a vane pump uses sliding vanes to move fluid through a system.

What is the difference between a heat engine and a heat pump?

Answer: A heat engine converts heat into mechanical work, while a heat pump moves heat from one location to another, typically from a cooler location to a warmer one.

What is the difference between a reciprocating engine and a rotary engine?

Answer: A reciprocating engine converts the reciprocating motion of a piston into rotational motion, while a rotary engine directly converts the rotational motion of a rotor into mechanical work.

What is the difference between a thermocouple and a RTD?

Answer: A thermocouple generates a voltage in response to a temperature difference between two conductors, while an RTD measures the resistance of a metal wire that changes with temperature.

What is the difference between a gasket and a seal?

Answer: A gasket is a compressible material used to create a seal between two surfaces, while a seal is a mechanical device used to prevent the leakage of fluids or gases.

What is the difference between a tensile and a compressive stress?

Answer: A tensile stress is a force that pulls apart or stretches a material, while a compressive stress is a force that pushes together or compresses a material.

What is the difference between a dead weight tester and a pressure gauge calibrator?

Answer: A dead weight tester uses known weights and an oil-filled piston cylinder to generate a precise pressure, while a pressure gauge calibrator uses an electronic reference standard to generate a precise pressure.

What is the difference between a jet engine and a rocket engine?

Answer: A jet engine uses air from the surrounding environment for propulsion, while a rocket engine carries its own oxidizer and fuel, allowing it to operate in the vacuum of space.

What is the difference between a propeller and a turbine?

Answer: A propeller is a rotating blade used to produce a thrust force, typically in air or water, while a turbine is a machine that converts the energy of a fluid flow into mechanical work.

What is the difference between a rectifier and an inverter?

Answer: A rectifier converts AC power to DC power, while an inverter converts DC power to AC power.

What is the difference between a compressor and an expander?

Answer: A compressor increases the pressure of a gas, while an expander decreases the pressure of a gas.

What is the difference between a solenoid valve and a control valve?

Answer: A solenoid valve is an electromechanical valve that is controlled by an electrical signal, while a control valve is a mechanical valve that is controlled by a mechanical or electronic signal.

What is the difference between a hydraulic system and a pneumatic system?

Answer: A hydraulic system uses a fluid, typically oil, to transmit power, while a pneumatic system uses compressed air to transmit power.

What is the difference between a servo motor and a stepper motor?

Answer: A servo motor is a motor that is controlled by a feedback signal to achieve precise positioning, while a stepper motor rotates in discrete steps, typically in response to electrical pulses.

What is the difference between a single-acting cylinder and a double-acting cylinder?

Answer: A single-acting cylinder uses fluid pressure to move the piston in only one direction, while a double-acting cylinder uses fluid pressure to move the piston in both directions.

What is the difference between a closed-loop control system and an open-loop control system?

Answer: A closed-loop control system uses feedback to adjust the output based on the desired input, while an open-loop control system does not use feedback and relies solely on the input to determine the output.

What is the difference between a limit switch and a proximity switch?

Answer: A limit switch is a mechanical switch that is actuated by physical contact, while a proximity switch is an electronic switch that is actuated by the presence or absence of a nearby object.

What is the difference between a solid-state relay and an electromechanical relay?

Answer: A solid-state relay uses semiconductor components to switch electrical loads, while an electromechanical relay uses mechanical components to switch electrical loads.

What is the difference between a CNC machine and a manual machine?

Answer: A CNC machine is controlled by a computer and can perform complex operations automatically, while a manual machine is operated by a person and requires manual input for each operation.

What is the difference between a microcontroller and a microprocessor?

Answer: A microcontroller is a self-contained computer system that includes a microprocessor, memory, and input/output peripherals, while a microprocessor is only a central processing unit and requires external components for memory and input/output.

What is the difference between a transmission and a gearbox?

Answer: A transmission is a mechanical device that transfers power from an engine to the wheels of a vehicle, while a gearbox is a device that changes the gear ratio between the engine and the transmission.

What is the difference between stress and strain?

Answer: Stress is the internal force per unit area of a material, while strain is the measure of deformation that results from stress.

What is the difference between hardness and toughness?

Answer: Hardness is the measure of a materialโ€™s resistance to indentation or scratching, while toughness is the measure of a materialโ€™s ability to withstand fracture under stress.

What is the difference between static and dynamic friction?

Answer: Static friction is the friction between two stationary objects, while dynamic friction is the friction between two objects in motion.

What is the difference between creep and fatigue?

Answer: Creep is the slow deformation of a material over time under a constant load, while fatigue is the degradation of a material due to repeated loading and unloading cycles.

What is the difference between a beam and a column?

Answer: A beam is a structural element that resists bending forces, while a column is a structural element that resists compression forces.

What is the difference between a cantilever and a simply supported beam?

Answer: A cantilever is a beam that is supported at one end and free at the other, while a simply supported beam is a beam that is supported at both ends.

What is the difference between a bearing and a bushing?

Answer: A bearing is a component that supports a rotating shaft or other moving parts, while a bushing is a component that provides a sliding surface for a rotating or moving shaft.

What is the difference between a chain drive and a belt drive?

Answer: A chain drive uses a chain to transmit power between two shafts, while a belt drive uses a belt to transmit power.

What is the difference between a helical gear and a spur gear?

Answer: A helical gear has teeth that are cut at an angle to the axis of rotation, while a spur gear has teeth that are cut parallel to the axis of rotation.

What is the difference between an impulse turbine and a reaction turbine?

Answer: An impulse turbine uses the kinetic energy of a high-velocity jet of fluid to rotate a turbine wheel, while a reaction turbine uses the pressure and velocity of a fluid to rotate a turbine wheel.

What is the difference between a lap joint and a butt joint?

Answer: A lap joint is a type of joint where two pieces of material overlap each other, while a butt joint is a type of joint where two pieces of material are joined end to end.

What is the difference between a compression spring and a tension spring?

Answer: A compression spring is a spring that is designed to resist compression, while a tension spring is a spring that is designed to resist tension or stretching.

What is the difference between an AC motor and a DC motor?

Answer: An AC motor is a motor that runs on alternating current, while a DC motor is a motor that runs on direct current.

What is the difference between a gasket and a seal?

Answer: A gasket is a mechanical component that is used to seal gaps between two mating surfaces, while a seal is a component that is used to prevent fluid or gas from escaping between two surfaces.

What is the difference between a centrifugal pump and a positive displacement pump?

Answer: A centrifugal pump uses centrifugal force to move fluid through a system, while a positive displacement pump uses mechanical means to move fluid through a system.

What is the difference between a closed-loop stepper motor and an open-loop stepper motor?

Answer: A closed-loop stepper motor is a stepper motor that is controlled using feedback to ensure accurate positioning, while an open-loop stepper motor is a stepper motor that is not controlled using feedback.

What is the difference between a thermocouple and a thermistor?

Answer: A thermocouple is a device that measures temperature based on the voltage produced by two dissimilar metals, while a thermistor is a device that measures temperature based on the resistance of a material.

What is the difference between a single-phase power supply and a three-phase power supply?

Answer: A single-phase power supply is a power supply that provides power on a single circuit, while a three-phase power supply provides power on three separate circuits.

What is the difference between a reciprocating compressor and a rotary compressor?

Answer: A reciprocating compressor compresses gas by using a piston to move gas into a chamber, while a rotary compressor compresses gas using a rotating impeller or screw.

What is the difference between a pressure vessel and a storage tank?

Answer: A pressure vessel is a vessel that is designed to contain fluids or gases at high pressure, while a storage tank is a vessel that is designed to contain fluids or gases at ambient pressure.

What is the difference between a bolt and a screw?

Answer: A bolt is a threaded fastener that is intended to be used with a nut to join two or more objects together, while a screw is a threaded fastener that is intended to be screwed into a material, such as wood or metal, without the use of a nut.

What is the difference between a solenoid and an electromagnet?

Answer: A solenoid is a coil of wire that generates a magnetic field when an electric current is passed through it, while an electromagnet is a type of solenoid that is designed to produce a stronger magnetic field by wrapping the wire around a magnetic core.

What is the difference between a surface grinder and a cylindrical grinder?

Answer: A surface grinder is a machine tool that is used to grind the surface of a workpiece to a high degree of flatness and accuracy, while a cylindrical grinder is a machine tool that is used to grind the outside diameter of cylindrical workpieces.

What is the difference between a shaft and an axle?

Answer: A shaft is a rotating component that is used to transmit power between two or more rotating objects, while an axle is a shaft that is designed to support and rotate a wheel or other load-bearing component.

What is the difference between a thermoplastic and a thermosetting plastic?

Answer: A thermoplastic is a type of plastic that can be melted and re-molded multiple times, while a thermosetting plastic is a type of plastic that hardens irreversibly when it is heated.

What is the difference between a jet engine and a rocket engine?

Answer: A jet engine uses atmospheric air as a source of oxygen to burn fuel and produce thrust, while a rocket engine carries its own supply of oxygen and fuel and can operate in a vacuum.

What is the difference between a worm gear and a spur gear?

Answer: A worm gear has teeth that are cut at an angle to the axis of rotation and is typically used for high reduction ratios, while a spur gear has teeth that are cut parallel to the axis of rotation and is typically used for low reduction ratios.

What is the difference between a transistor and a diode?

Answer: A transistor is a semiconductor device that can amplify or switch electronic signals, while a diode is a semiconductor device that allows current to flow in only one direction.

What is the difference between a flange and a fitting?

Answer: A flange is a flat or raised surface that is used to attach one object to another, while a fitting is a component that is used to connect pipes, valves, or other components together.

What is the difference between a closed-loop control system and an open-loop control system?

Answer: A closed-loop control system uses feedback to adjust the output of a system to achieve a desired result, while an open-loop control system does not use feedback and relies on pre-determined inputs to achieve a desired output.

What is the difference between laminar flow and turbulent flow?

Answer: Laminar flow is a smooth and orderly flow of fluid, where the layers of fluid move parallel to each other, while turbulent flow is a chaotic and disorderly flow of fluid, where the layers of fluid mix and swirl.

What is the difference between a stepper motor and a servo motor?

Answer: A stepper motor moves in precise steps, with each step being a fixed angle, while a servo motor rotates continuously and can be controlled to move to a specific position.

What is the difference between a strain gauge and a load cell?

Answer: A strain gauge is a sensor that measures the amount of strain or deformation in a material, while a load cell is a transducer that measures the force or weight applied to a structure or component.

What is the difference between a microcontroller and a microprocessor?

Answer: A microcontroller is a small computer on a single integrated circuit that is designed to control specific functions, while a microprocessor is a general-purpose computing device that is designed to execute a variety of tasks.

What is the difference between a reciprocating engine and a rotary engine?

Answer: A reciprocating engine converts linear motion into rotational motion, while a rotary engine generates rotary motion directly.

What is the difference between a flywheel and a pulley?

Answer: A flywheel is a rotating mass that is used to store energy and smooth out fluctuations in a systemโ€™s motion, while a pulley is a rotating wheel with a grooved rim that is used to transmit power and change the direction of force.

What is the difference between a gear pump and a vane pump?

Answer: A gear pump uses gears to create flow and is typically used for high-pressure applications, while a vane pump uses vanes that slide in and out of a rotor to create flow and is typically used for low-pressure applications.

What is the difference between an analog signal and a digital signal?

Answer: An analog signal is a continuous signal that varies in amplitude, frequency, or phase over time, while a digital signal is a discrete signal that is composed of binary digits or bits.

What is the difference between a single-stage compressor and a multi-stage compressor?

Answer: A single-stage compressor compresses air in a single stroke, while a multi-stage compressor compresses air in multiple stages to achieve higher pressures.

What is the difference between a laser and an LED?

Answer: A laser is a device that emits a narrow, intense beam of light with a specific wavelength and coherence, while an LED is a device that emits a broader spectrum of light with less coherence.


What is the difference between a pressure relief valve and a safety valve?

Answer: A pressure relief valve is designed to protect equipment or systems from overpressure by relieving excess pressure to prevent damage or failure, while a safety valve is designed to protect personnel from harm by relieving pressure before it reaches dangerous levels.

What is the difference between a closed-loop system and an open-loop system?

Answer: In a closed-loop system, feedback is used to adjust the systemโ€™s output based on its performance, while in an open-loop system, there is no feedback and the output is fixed.

What is the difference between a radiator and a heat exchanger?

Answer: A radiator is a heat exchanger that is used to transfer heat from a hot fluid to the air, while a heat exchanger is a device that transfers heat between two fluids without allowing them to mix.

What is the difference between a linear actuator and a rotary actuator?

Answer: A linear actuator moves in a straight line, while a rotary actuator rotates about an axis.

What is the difference between an elevator and an escalator?

Answer: An elevator is a vertical transport device that moves people or goods between different floors of a building, while an escalator is a continuously moving staircase that transports people from one level to another.

What is the difference between a centrifugal pump and a positive displacement pump?

Answer: A centrifugal pump uses a rotating impeller to create flow, while a positive displacement pump moves fluid by trapping a fixed amount of it and then forcing it through the pump.

What is the difference between a clutch and a brake?

Answer: A clutch is used to engage or disengage power transmission between a driving shaft and a driven shaft, while a brake is used to slow or stop motion.

What is the difference between a bolt and a screw?

Answer: A bolt is a threaded fastener that is used with a nut to join two or more objects, while a screw is a threaded fastener that is designed to be turned into a material to secure it in place.

What is the difference between a metal and a non-metal?

Answer: Metals are elements that are typically hard, shiny, and good conductors of heat and electricity, while non-metals are elements that are typically brittle, dull, and poor conductors of heat and electricity.

What is the difference between a conductor and an insulator?

Answer: A conductor is a material that allows electric current to flow through it easily, while an insulator is a material that does not allow electric current to flow through it easily.


What is the difference between a bearing and a bushing?

Answer: A bearing is a machine element that supports a rotating shaft or other moving parts and reduces friction between them, while a bushing is a type of bearing that is typically cylindrical in shape and is used to provide support for a shaft.

What is the difference between a fan and a blower?

Answer: A fan is a device that moves air or other gases using rotating blades, while a blower is a device that uses an impeller to move air or other gases at a higher pressure than a fan.

What is the difference between a worm gear and a spur gear?

Answer: A worm gear is a type of gear that consists of a worm (a cylindrical rod with a spiral thread) and a worm wheel (a gear that meshes with the worm), while a spur gear is a type of gear that has straight teeth and is typically used to transmit power between parallel shafts.

What is the difference between a flywheel and a governor?

Answer: A flywheel is a rotating mechanical device that is used to store energy and smooth out fluctuations in power output, while a governor is a device that controls the speed of an engine or other machine by regulating the flow of fuel or other input.

What is the difference between a static and a dynamic load?

Answer: A static load is a load that is applied to a structure or machine while it is at rest, while a dynamic load is a load that is applied to a structure or machine while it is in motion.

What is the difference between a plasma and a gas?

Answer: Plasma is a state of matter that is similar to a gas but has additional energy, such as heat or an electric charge, which allows it to conduct electricity and exhibit other unique properties.

What is the difference between a ductile and a brittle material?

Answer: A ductile material is one that can be deformed plastically without fracturing, while a brittle material is one that fractures without significant deformation under stress.

What is the difference between a cam and a follower?

Answer: A cam is a mechanical device that is used to convert rotary motion into linear motion, while a follower is a component that moves in response to the motion of a cam.

What is the difference between a turbine and an engine?

Answer: A turbine is a machine that converts the energy of a fluid into rotational energy, while an engine is a machine that converts the energy of fuel into mechanical energy.

What is the difference between a thread and a bolt?

Answer: A thread is a helical ridge that is cut into a material to form a screw or other threaded component, while a bolt is a type of fastener that has a threaded shaft and is typically used with a nut to join two or more objects.


What is the difference between torque and horsepower?

Answer: Torque is a measure of the force that causes an object to rotate around an axis or pivot point, while horsepower is a measure of the power output of an engine or other machine.

What is the difference between a heat engine and a refrigeration cycle?

Answer: A heat engine is a device that converts thermal energy into mechanical energy, while a refrigeration cycle is a process that moves thermal energy from a cold space to a warm space, requiring an input of mechanical energy.

What is the difference between a strut and a shock absorber?

Answer: A strut is a structural component that provides support and stiffness to a vehicleโ€™s suspension system, while a shock absorber is a device that dampens the oscillation of the suspension system by converting the kinetic energy of the suspension into heat.

What is the difference between a thermocouple and a thermistor?

Answer: A thermocouple is a device that measures temperature by detecting the voltage generated by two dissimilar metals when they are heated, while a thermistor is a type of resistor whose resistance changes with temperature.

What is the difference between a stepper motor and a servo motor?

Answer: A stepper motor is a type of motor that rotates in small, precise steps, while a servo motor is a type of motor that uses feedback to maintain a specific position or speed.

What is the difference between a monocoque and a space frame chassis?

Answer: A monocoque chassis is a type of construction where the structural skin of a vehicle or aircraft provides the primary structural support, while a space frame chassis is a type of construction where the load-bearing structure is made up of a series of interconnected tubes or beams.

What is the difference between a piston engine and a rotary engine?

Answer: A piston engine is a type of internal combustion engine that uses reciprocating pistons to convert pressure into mechanical energy, while a rotary engine is a type of engine that uses a rotating rotor to generate mechanical energy.

What is the difference between a proportional and an integral controller?

Answer: A proportional controller adjusts the control output based on the difference between the desired value and the current value of the controlled variable, while an integral controller adjusts the control output based on the accumulated error over time.

What is the difference between a pneumatic and a hydraulic system?

Answer: A pneumatic system uses compressed air to transmit and control power, while a hydraulic system uses pressurized fluid (usually oil or water) to transmit and control power.

What is the difference between a crankshaft and a camshaft?

Answer: A crankshaft is a rotating shaft that converts reciprocating motion into rotational motion, while a camshaft is a rotating shaft with an eccentric lobe that is used to operate the valves in an engine.


What is the difference between a worm gear and a spur gear?

Answer: A worm gear is a type of gear that consists of a threaded shaft (worm) and a toothed wheel (worm wheel), while a spur gear is a type of gear with straight teeth that mesh with another spur gear.

What is the difference between a gauge pressure and an absolute pressure?

Answer: Gauge pressure is the pressure difference between a system and the atmospheric pressure, while absolute pressure is the total pressure exerted on a system, including atmospheric pressure.

What is the difference between a matrix and a tensor?

Answer: A matrix is a rectangular array of numbers or symbols, while a tensor is a mathematical object that generalizes the notion of scalars, vectors, and matrices to higher dimensions.

What is the difference between a propeller and a turbine?

Answer: A propeller is a device that converts rotational motion into thrust by accelerating air or water, while a turbine is a device that converts the energy of a fluid into mechanical energy by rotating blades.

What is the difference between a centrifugal pump and a positive displacement pump?

Answer: A centrifugal pump is a type of pump that uses a rotating impeller to create a flow of fluid, while a positive displacement pump is a type of pump that uses a mechanical mechanism to displace a fixed volume of fluid.

What is the difference between an open-loop and a closed-loop control system?

Answer: An open-loop control system is a system where the output is not fed back to the input for error correction, while a closed-loop control system is a system where the output is fed back to the input for error correction.

What is the difference between a ductile material and a brittle material?

Answer: A ductile material is a material that can deform under stress before breaking, while a brittle material is a material that fractures without significant deformation under stress.

What is the difference between a load cell and a force transducer?

Answer: A load cell is a type of transducer that converts a mechanical force into an electrical signal, while a force transducer is a type of sensor that measures the amount of force applied to it.

What is the difference between a differential and an integral equation?

Answer: A differential equation describes the rate of change of a variable with respect to another variable, while an integral equation describes the relationship between a function and an integral of that function.

What is the difference between a cross flow and a counter flow heat exchanger?

Answer: In a cross flow heat exchanger, the fluids flow perpendicular to each other, while in a counter flow heat exchanger, the fluids flow in opposite directions.


What is the difference between a horizontal and a vertical axis wind turbine?

Answer: A horizontal axis wind turbine (HAWT) has its rotor shaft parallel to the ground and its blades rotate around a horizontal axis, while a vertical axis wind turbine (VAWT) has its rotor shaft perpendicular to the ground and its blades rotate around a vertical axis.

What is the difference between a jib and a boom in a crane?

Answer: A jib is an extension arm that is attached to the craneโ€™s main boom and provides additional reach, while a boom is the main arm of the crane that supports the load.

What is the difference between a cantilever beam and a simply supported beam?

Answer: A cantilever beam is a beam that is fixed at one end and free at the other end, while a simply supported beam is a beam that is supported at both ends and is free to deflect in the middle.

What is the difference between a pulley and a sheave?

Answer: A pulley is a type of wheel with a grooved rim that rotates around an axle, while a sheave is a specific type of pulley that is designed to guide a rope or cable.

What is the difference between a cam and a follower?

Answer: A cam is a mechanical device that converts rotational motion into linear motion, while a follower is a device that rides on the camโ€™s surface and translates the camโ€™s motion into a specific type of output motion.

What is the difference between a flange and a gasket?

Answer: A flange is a flat or raised ring that is used to connect two pipes or other components, while a gasket is a compressible material that is placed between the flanges to create a seal.

What is the difference between a lap joint and a butt joint?

Answer: A lap joint is a type of joint where two overlapping pieces are joined together, while a butt joint is a type of joint where the two pieces are joined end-to-end.

What is the difference between a static and dynamic load?

Answer: A static load is a load that does not change over time, while a dynamic load is a load that varies with time.

What is the difference between a thermoplastic and a thermosetting polymer?

Answer: A thermoplastic is a polymer that can be melted and reshaped multiple times without significant chemical change, while a thermosetting polymer is a polymer that, once cured, cannot be melted or reshaped.

What is the difference between torque and moment of force?

Answer: Torque and moment of force both refer to the twisting or turning effect of a force, but torque is generally used to describe rotational motion, while moment of force can refer to either rotational or linear motion.


What is the difference between a pneumatic and hydraulic system?

Answer: A pneumatic system uses compressed air to transmit power, while a hydraulic system uses a fluid (usually oil) to transmit power.

What is the difference between a positive displacement pump and a centrifugal pump?

Answer: A positive displacement pump moves fluid by trapping a fixed amount of fluid and forcing it through the pumpโ€™s outlet, while a centrifugal pump uses an impeller to generate centrifugal force that pushes the fluid through the pumpโ€™s outlet.

What is the difference between a gear and a sprocket?

Answer: A gear is a rotating component with teeth that mesh with another gear to transmit power, while a sprocket is a rotating component with teeth that mesh with a chain to transmit power.

What is the difference between a gear train and a gear reducer?

Answer: A gear train is a system of gears that transmits power from one rotating component to another, while a gear reducer is a type of gear train that reduces the speed of the output shaft relative to the input shaft.

What is the difference between a compressor and a vacuum pump?

Answer: A compressor is a device that pressurizes air or gas, while a vacuum pump is a device that creates a vacuum by removing air or gas from a sealed container.

What is the difference between a clutch and a brake?

Answer: A clutch is a device that connects and disconnects rotating components, while a brake is a device that slows down or stops rotating components.

What is the difference between a thermocouple and a RTD (Resistance Temperature Detector)?

Answer: A thermocouple is a temperature sensor that produces a voltage proportional to the temperature difference between two junctions, while a RTD is a temperature sensor that measures the change in resistance of a metal wire as the temperature changes.

What is the difference between a jack and a hoist?

Answer: A jack is a device that is used to lift a vehicle or other heavy object off the ground, while a hoist is a device that is used to lift and move heavy objects over a larger distance.

What is the difference between a stepper motor and a servo motor?

Answer: A stepper motor rotates in discrete steps, while a servo motor rotates continuously and can be controlled to rotate to a specific position.

What is the difference between ductile and brittle materials?

Answer: Ductile materials can undergo significant plastic deformation before fracturing, while brittle materials fracture without significant plastic deformation.


What is the difference between a worm gear and a spur gear?

Answer: A worm gear has a screw-like shaft that meshes with a gear to transmit power, while a spur gear has a straight shaft with teeth that mesh with another gear to transmit power.

What is the difference between a spring and a shock absorber?

Answer: A spring is a mechanical component that stores and releases energy to absorb shocks or maintain a desired position, while a shock absorber is a component that dissipates energy to reduce vibrations or cushion impacts.

What is the difference between a piston and a cylinder?

Answer: A piston is a cylindrical component that moves back and forth within a cylinder to transmit power, while a cylinder is a hollow component that contains the piston and allows for the transfer of fluids or gases.

What is the difference between a single-stage compressor and a multi-stage compressor?

Answer: A single-stage compressor compresses air or gas in one step, while a multi-stage compressor compresses the air or gas in multiple stages, using intermediate cooling between stages to increase efficiency.

What is the difference between a gear pump and a vane pump?

Answer: A gear pump uses rotating gears to move fluid, while a vane pump uses vanes that slide in and out of a rotor to move fluid.

What is the difference between a heat exchanger and a condenser?

Answer: A heat exchanger is a device that transfers heat between two fluids without allowing them to mix, while a condenser is a device that removes heat from a vapor and converts it into a liquid.

What is the difference between a camshaft and a crankshaft?

Answer: A camshaft is a rotating shaft with one or more eccentric lobes that operate the engineโ€™s valves, while a crankshaft is a rotating shaft that converts reciprocating motion (up and down) into rotational motion.

What is the difference between an AC motor and a DC motor?

Answer: An AC motor operates on alternating current and uses an alternating magnetic field to rotate the rotor, while a DC motor operates on direct current and uses a magnetic field created by the current flowing through the stator to rotate the rotor.

What is the difference between an internal combustion engine and an external combustion engine?

Answer: In an internal combustion engine, fuel is burned inside the engine to generate power, while in an external combustion engine, fuel is burned outside the engine to generate heat, which is then transferred to the engine to generate power.

What is the difference between a screw and a bolt?

Answer: A screw is a threaded fastener that is designed to be threaded into a material, while a bolt is a threaded fastener that is designed to be passed through a material and secured with a nut on the other side.


What is the difference between a turbocharger and a supercharger?

Answer: A turbocharger is a compressor that is driven by exhaust gases to increase the amount of air going into an internal combustion engine, while a supercharger is a compressor that is mechanically driven by a belt or chain to increase the amount of air going into an internal combustion engine.

What is the difference between a fixed-displacement pump and a variable-displacement pump?

Answer: A fixed-displacement pump has a set flow rate that cannot be adjusted, while a variable-displacement pump can adjust its flow rate to meet changing demands.

What is the difference between an open-loop control system and a closed-loop control system?

Answer: An open-loop control system does not have a feedback mechanism to correct its output, while a closed-loop control system uses feedback to adjust its output.

What is the difference between a shear stress and a normal stress?

Answer: A shear stress is a stress that occurs when two forces are applied to an object in opposite directions parallel to each other, while a normal stress is a stress that occurs when a force is applied perpendicular to a surface.

What is the difference between ductile and brittle materials?

Answer: Ductile materials are able to deform plastically without breaking, while brittle materials fracture or break without any significant deformation.

What is the difference between a linear actuator and a rotary actuator?

Answer: A linear actuator produces linear motion, while a rotary actuator produces rotational motion.

What is the difference between a valve and a gate?

Answer: A valve is a device that regulates the flow of a fluid or gas, while a gate is a device that completely stops or allows the flow of a fluid or gas.

What is the difference between a torque converter and a clutch?

Answer: A torque converter is a fluid coupling device that transmits power from an engine to a transmission, while a clutch is a mechanical coupling device that engages and disengages power transmission between an engine and a transmission.

What is the difference between a bearing and a bushing?

Answer: A bearing is a machine element that reduces friction between moving parts, while a bushing is a fixed cylindrical component that provides a bearing surface for a rotating shaft.

What is the difference between a strain gauge and a load cell?

Answer: A strain gauge is a sensor that measures strain or deformation in a material, while a load cell is a transducer that converts force or weight into an electrical signal.


What is the difference between a pressure vessel and a storage tank?

Answer: A pressure vessel is designed to withstand high pressure, while a storage tank is designed to hold liquids or gases at atmospheric pressure.

What is the difference between a reciprocating compressor and a centrifugal compressor?

Answer: A reciprocating compressor compresses gas by using a piston to decrease the volume of the gas, while a centrifugal compressor compresses gas by using a high-speed impeller to impart kinetic energy to the gas, which is then converted to pressure.

What is the difference between a synchronous motor and an induction motor?

Answer: A synchronous motor rotates at a fixed speed that is synchronized with the frequency of the electrical supply, while an induction motorโ€™s speed varies depending on the load.

What is the difference between a stepper motor and a servo motor?

Answer: A stepper motor moves in small, precise steps in response to digital signals, while a servo motor rotates continuously and can be controlled with analog signals to achieve precise positioning.

What is the difference between a pulley and a sprocket?

Answer: A pulley is a wheel with a grooved rim that is used with a belt or rope to transmit power, while a sprocket is a wheel with teeth that is used with a chain to transmit power.

What is the difference between a worm gear and a spur gear?

Answer: A worm gear consists of a screw-like gear and a gear with teeth that mesh with the screw, while a spur gear has teeth that mesh directly with another gearโ€™s teeth.

What is the difference between a thermocouple and a resistance temperature detector (RTD)?

Answer: A thermocouple measures temperature by the voltage produced at the junction of two different metals, while an RTD measures temperature by the change in resistance of a metal wire as it heats up.

What is the difference between a closed-cycle gas turbine and an open-cycle gas turbine?

Answer: A closed-cycle gas turbine uses a working fluid that is recycled through the turbine, while an open-cycle gas turbine uses air from the atmosphere as the working fluid.

What is the difference between a two-stroke engine and a four-stroke engine?

Answer: A two-stroke engine completes a cycle in two strokes of the piston (one up and one down), while a four-stroke engine completes a cycle in four strokes of the piston (intake, compression, power, and exhaust).

What is the difference between a bending moment and a torsional moment?

Answer: A bending moment is a moment that produces bending stresses in a structure, while a torsional moment is a moment that produces twisting stresses in a structure.


What is the purpose of a governor in an engine?

Answer: A governor in an engine is used to regulate the speed of the engine by controlling the fuel flow to the engine.

What is a torque converter?

Answer: A torque converter is a type of fluid coupling that is used in automatic transmissions to transfer power from the engine to the transmission.

What is a shock absorber?

Answer: A shock absorber is a device that is used to dampen the vibrations and shocks that are produced by a vehicleโ€™s suspension system.

What is the purpose of a flywheel in an engine?

Answer: A flywheel in an engine is used to store energy and smooth out the fluctuations in power that are produced by the engineโ€™s combustion cycle.

What is a camshaft?

Answer: A camshaft is a rotating shaft that is used to control the opening and closing of the engineโ€™s valves.

What is the difference between a ladder frame and a unibody frame?

Answer: A ladder frame is a type of frame that consists of two longitudinal rails that are connected by cross members, while a unibody frame is a type of frame that integrates the vehicleโ€™s body and frame into a single structure.

What is a crankshaft?

Answer: A crankshaft is a rotating shaft that is used to convert the reciprocating motion of the engineโ€™s pistons into rotary motion.

What is a fuel cell?

Answer: A fuel cell is an electrochemical device that converts the energy from the reaction between hydrogen and oxygen into electrical energy.

What is a turbocharger?

Answer: A turbocharger is a device that is used to increase the power output of an engine by compressing the intake air.

What is a heat exchanger?

Answer: A heat exchanger is a device that is used to transfer heat from one fluid to another, without the fluids coming into contact with each other.


What is the difference between a two-stroke engine and a four-stroke engine?

Answer: A two-stroke engine completes a power cycle in two strokes of the piston, while a four-stroke engine completes a power cycle in four strokes of the piston.

What is a clutch?

Answer: A clutch is a device that is used to engage and disengage the engineโ€™s power from the transmission, allowing the driver to change gears.

What is a differential?

Answer: A differential is a device that is used to transfer power from the engine to the wheels, while allowing the wheels to rotate at different speeds.

What is a radiator?

Answer: A radiator is a device that is used to dissipate the heat that is generated by the engineโ€™s cooling system.

What is a catalytic converter?

Answer: A catalytic converter is a device that is used to reduce the emissions of harmful pollutants from the engineโ€™s exhaust system.

What is an alternator?

Answer: An alternator is a device that is used to generate electrical power for the vehicleโ€™s electrical system, by converting the rotational energy of the engine into electrical energy.

What is a carburetor?

Answer: A carburetor is a device that is used to mix air and fuel in the correct ratio for combustion in the engine.

What is an EGR valve?

Answer: An EGR valve is a device that is used to reduce the emissions of harmful pollutants from the engine, by recirculating a portion of the exhaust gases back into the engineโ€™s intake system.

What is a turbofan engine?

Answer: A turbofan engine is a type of jet engine that is used in aircraft, and is designed to be more fuel-efficient and quieter than traditional jet engines.

What is a powertrain?

Answer: A powertrain is the system that is responsible for generating power and transferring it to the vehicleโ€™s wheels, including the engine, transmission, and drivetrain components.


What is an exhaust manifold?

Answer: An exhaust manifold is a component that is used to collect and direct the exhaust gases from the engineโ€™s cylinders into the exhaust system.

What is a camber angle?

Answer: Camber angle is the angle between the vertical axis of the wheel and the axis of the wheelโ€™s contact patch with the road. It is used to improve handling and stability.

What is a suspension system?

Answer: A suspension system is a system of springs, shock absorbers, and other components that are used to support the vehicleโ€™s weight, absorb shocks and vibrations, and provide stability and control while driving.

What is a power steering system?

Answer: A power steering system is a system that is used to assist the driver in turning the steering wheel by applying hydraulic pressure to the steering mechanism.

What is a hydraulic system?

Answer: A hydraulic system is a system that uses pressurized fluid to transmit power and energy from one location to another.

What is a crankcase ventilation system?

Answer: A crankcase ventilation system is a system that is used to remove excess gases and vapors from the engineโ€™s crankcase and redirect them into the engineโ€™s intake system.

What is a leaf spring?

Answer: A leaf spring is a type of suspension system that consists of several layers of metal strips, which are designed to flex and absorb shocks and vibrations.

What is a disc brake?

Answer: A disc brake is a type of brake system that uses a rotor and caliper to clamp down on a rotating disc attached to the wheel, in order to slow down or stop the vehicle.

What is a torsion bar suspension?

Answer: A torsion bar suspension is a type of suspension system that uses a long metal bar that is twisted to provide support and resistance against the weight of the vehicle.

What is an OBD system?

Answer: An OBD (On-Board Diagnostics) system is a system that is built into modern vehicles to monitor and diagnose the performance of various components and systems, and to alert the driver to any problems or malfunctions.


Leave a Comment